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Patented May 26, 1931 UNITED STATES PATENT OFFICE FACTURING assocmrns, or LunLow, sETrs MASSACHUSETTS,- A TRUST OF MASSACHU- No Drawing. Original application filed September 29, 1930, Serial No. 485,328. Divided and this application filed April 14, 1931. Serial II'o. 530,154.

This invention relates to improvements in shoes sewed with an improved linen shoe thread specially treated to preserve it against 'ly in order to the deteriorating conditions to which it is subjected when used in the shoes. More particularly, the invention relates to improvements in shoes sewed with an unboiled linen thread with its normal content of pectin, hemi-cellulose and other non-cellulose constituents which is preserved so that itis particularly adapted for" use in shoes, for example, as a welt thread in place of the boiled linen thread or cheaper cotton thread now commonly employed for shoe manufacture.

In shoe manufacture the uppers are sewed to the welts by shoe thread which is usually linen thread for the bettergrades of shoes and cotton thread for the cheaper grades of shoes. Similarly, in sewing the outer edges of the soles of shoes linen thread is used for the better grades of shoes and cotton thread for the cheaper grades.

The linen thread which is commonly used for shoe thread is a so-called boiled thread,

made by boiling the yarn from which the thread is made, in a dilute solution of caustic soda and soda ash which dissolves out the greater part of the pectin, hemi-cellulose and non-cellulose constituents, giving what is known in the trade as a boiled yarn, from which linen shoe thread is now made. In this way the xflax is freed more or less completely from the non-cellulose constituents which readily undergo deterioration or decomposition by micro-organisms; and it has heretofore been considered necessary to remove such constituents more or less completeproduce a satisfactory linen shoe thread. v

The shoe thread of shoes is subjected to conditions .which favor and promote deterioration or decomposition of the shoe thread, and particularly of shoe thread which contains any substantial amount of readily decomposable constituents which are decomposed by mold or bacterial action. Shoes in the ordinary course of wear come into contact with street dirt, dust, mud, etc.,and it is well known that ordinary street dirt and dust, etc. are contaminated with or contain numerous micro-organisms, such as molds, bacteria, etc. In rainy weather shoes come in contact with wet sidewalks and streets or with wet dirt or mud and the water penetrates the shoe to a greater or less extent, carrying with it contaminated micro-organisms. Leather shoes are also kept more or less moist by perspiration, particularly in the summer time and in humid weather. When shoes become wet or moist either through rainy weather or through perspiration with improper opportunity for drying out, the con-. ditions are favorable for the rapid growth and development of molds and bacteria which are present in shoes which have been worn for anylength of time. When shoes are worn day after dayand particularly in rainy weather or in hot, humid weather and are not permitted to dry out properly favorable conditions are presented for development and growth of destructive micro-organisms. Even boiled linen thread and cotton thread are not immune from such micro-organisms.

I have investigated the action of microorganisms from street dirt on unboiled linen shoe thread and I have found that under favorable conditions of moisture and temperature such thread undergoes rapid deterioration. I have found, however, that by incorporating in the unboiled linen thread a suitable disinfectant the thread can be preserved and made resistant to such microorganisms and can thereby be made available for use as a valuable substitute for boiled linen shoe thread and for cotton shoe thread. I have also found that even the boiled linen thread can be improved in its resistance to deterioration by similarly incorporating a suitable disinfectant therein.

The disinfectants which I employ in the treatment of the shoe thread are disinfectants which are of a more or less permanent character and which remain in the shoe thread and impart to it resistance to decomposition or deterioration by such destructive microorganisms as are found in street dirt, mud

and the like with which shoes are continually brought in contact in every day use. The disinfectant may kill or destroy the moulds, bacteria or micro-organisms by reason of its toxic poisoning action, or the disinfectant may produce a state of suspended grow h by reason of a toxic poisoning action less drastic than that required. to kill or destroy the or.- ganisms; or the disinfectants may kill or destroythe moulds, bacteria or micro-organisms or produce a state of suspended growth by reason of its dehydrating action on the material treated or on the organisms themselves. Certain disinfectants may exhibit a combined poisoning and dehydrating action. Merely boiling the thread without alkali, whereby the thread is subjected to a sterilization by heat alone, is not suflicient to preserve the thread against attack by micro-organisms normally accompanying unboiled thread, or to be found in street dirt or the like.

The disinfectant which I have found particularly advantageous and efl'ective is a dyestuff known in the trade as brilliant green, which belongs to the triphenyl methane series of coloring matters and is chemically designated as the sulfate or double zinc chloride of tetra ethyl diamido-triphenyl-carbinol. Other dyestufls which have a disinfecting and preservative action can be used, including other dyestufi's of the triphenyl methane series which have such a disinfecting and preservative action. Other substances than dyestufis can also be used as disinfectants or preservatives, including sodium silico fluoride, sodium phenyl phenate and certain copper salts which have a disinfecting and preservative action.

The amount of disinfectant which is incorporated in the thread will vary with different disinfectants and may vary with the same disinfectant. In the case of brilliant green incorporation of as little as one part of the dye in ten thousand parts of the thread by weight is efi'ective in retarding mold and bacterial growth, but larger amounts can be used, particularly for tropical climates or other places where the shoes are subjected to unusually severe conditions promoting deterioration or decomposition of the linen thread. In some cases as much as 1% or more of antiseptic may be incorporated in the thread although ordinarily a much smaller amount will be sufiicient.

I have found that even boiled linen shoe thread can be improved in its resistance to deterioration by similarly incorporating a disinfectant or preservative in it, thereby giving an improved boiled linen shoe thread; but in the case of such a boiled shoe thread the cost of manufacture is increased by the boiling operation and the amount of shoe thread produced from the flax is correspondingly decreased as compared with the improved unboiled shoe thread above described. While therefore the invention in its broader aspects includes shoes sewed with an improved boiled shoe thread, the use of the unboiled linen shoe thread treated according tdthe invention has many advantages, such unboiled thread being distinguished from boiled shoe thread by their content of all of the normal constituents of the fiax fiber as well as by the presence of the preservative or disinfectant, and in other respects such as those above referred to.

When the shoes of the present invention are worn and subjected to the varying con ditions of use where they come into contact with street dirt, dust, mud, etc., and when the improved shoe threads used in the shoes come into contact with and become infected by various micro-organisms, and when conditions of moisture and temperature are favorable for the growth of such micro-organisms, the shoes are resistant to deterioration thereby. Thus, even when the shoes remain moist and warm for considerableperiods of time as in rainy or humid weather, or where proper opportunity is not provided for drying out the shoes, the objectionable deterioration of the shoe thread which would otherwise take place is prevented or retarded or minimized, thereby insuring that the shoe thread will retain its strength and giving longer life to the shoe, particularly under unfavorable conditions of use. The welt thread, which is employed for sewing the uppers of the shoe to the welt and which is close to the foot of the wearer so that it is kept warm and, in warm or humid weather, is kept moist by perspiration is nevertheless preserved against objectionable deterioration by micro-organisms which gain access to it and which would otherwise cause more rapid deterioration of the shoe thread. Similarly the shoe threads used for sewing the outer edge of the soles of the shoe and which are commonly exposed to the atmosphere and to dust, dirt, mud, etc. both on the top and the bottom of the sole are preserved against deterioration such as would other ise tend to occur more rapidly. Thus, even the unboiled shoe thread, when subjected to such adverse conditions in the shoe, is comparable with or may even be superior to the ordinary boiled shoe thread; while the boiled shoe thread which is preserved in accordance with the present invention will be materially improved in its re sistance to such deterioration. .The present invention accordingly makes it possible to insure that high grade shoes made of high grade leather can be sewed together with t e improved shoe thread of the present invention, thereby insuring the maximum life and utility of the shoe as a whole.

This application is a division of In prior application Serial No. 485,328 filed eptember 29, 1930.

. I claim:

1. A shoe sewed with a linen shoe thread having a small amount of a posioning or dehydrating disinfectant incorporated therein to preserve the shoe thread against objectionable deterioration by micro-organisms in street dirt and the like.

2 A shoe sewed with an unboiled linen shoe thread containing the normal non-cellulose constituents of the flax fiber and having a small amount of a poisoning or dehydrating disinfectant incorporated therein to preserve the shoe thread against objectionable deterioration by micro-organisms in street dirt and the like.

3. A shoe sewed with a linen shoe thread having a small amount of a triphenyl methane dye incorporated therein to preserve the shoe thread against objectionable deterioration by micro-organisms in street dirt and the like.

4. A shoe sewed with an unboiled linen shoe thread containing the normal non-cellulose constituents of flax fiber and having a small amount of brilliant green dye incorporated therein to preserve the shoe thread against objectionable deterioration by microorganisms in street dirt and the like.

5. A shoe sewed with a linen shoe thread having a small amount of sodium silico fluo- 25 ride incorporated therein to preserve the shoe thread against objectionable deteriora- {ign by micro-organisms in street dirt and the 6. A shoe sewed with a linen shoe thread 30 having a small amount of sodium phenyl phenate incorporated therein to preserve the shoe thread against objectionable deterioratilon by micro-organisms in street dirt and the 1 (e. M In testimony whereof I afiix my signature.

" WALTER w. EVANS. 

